This is system C the memory is manually managed with malloc(). You can't simply nil the reference and expect GC to come through and clean it for you, you have to issue a free() for each malloc() that was called. While it might be possible to write a custom disposal routine that does that efficiently for the structure, the simpler way is to just use the normal functions you use for removing single items and call it against everything. Doing that will not be as efficient because those functions keep the structure in a consistent state and don't perform bulk operations, but they have already been written and tested, and in normal use cases they won't be a bottle neck.
> You can't simply nil the reference and expect GC to come through and clean it for you
This is exactly what happens when your process exits and its private memory space is freed in its entirety. Hence the discussion. There's no need to clean up before exit, except if you want to (i) use a leak checker; or (ii) run on a machine with no MMU.
